SOLAR PHOTOVOLTAIC
ENERGY
Introduction
Photovoltaics (PV) is a technology that converts
sunlight directly into electricity. It was first observed
in 1839 by the French scientist Becquerel who
detected that when light was directed onto one side of
a simple battery cell, the current generated could be
increased. In the late 1950s, the space programme
provided the impetus for the development of
crystalline silicon solar cells; the first commercial
production of PV modules for terrestrial applications
began in 1953 with the introduction of automated PV
production plants.
Today, PV systems have huge value use in areas
remote from an electricity grid where they can provide
power for water pumping, lighting, vaccine
refrigeration, electrified livestock fencing,
telecommunications and many other applications.
With the global demand to reduce carbon dioxide
emissions, PV technology is also gaining popularity as
a mainstream form of electricity generation.
Several million solar PV systems are currently in use
worldwide, with an installed capacity of 40GW globally
by the end of 2010 (Renewables 2011Global Status
Report), yet this is a tiny proportion of the vast
potential that exists for PV as an energy source.
Figure 1: A photovoltaic panel being set up in
rural Peru for domestic solar lighting. Photo
credit: Practical Action / Marco Antonio
Arango.
Photovoltaic modules provide an independent, reliable
electrical power source at the point of use, making PV particularly suited to remote locations.
However, solar PV is increasingly being used in homes and offices for electricity to replace or
supplement grid power, often in the form of solar PV roof tiles. The daylight needed is free, but the
cost of equipment can take many years to achieve payback. However, in remote areas where grid
connection is expensive, PV can be the most cost effective power source.
The use of PV electricity in developing countries
Most of the world’s developing countries are within the tropics and hence have ample solar insolation
(the total energy per unit area received from the sun). The tropical regions also benefit from having
only a small seasonal variation of solar insolation, even during the rainy season, which means that,
unlike northern industrial countries, solar energy can be harnessed economically throughout the year.
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